Determining suitability for disconnection from power outlet of a power distribution unit based on status of power supplies of a hardware device

ABSTRACT

A programmable logic circuit assigns a value to an outlet of a power distribution unit (PDU) that comprises a power source at an input of the PDU and at least one light-emitting diode (LED) associated with the outlet. The programmable logic circuit sends the value to a program on a hardware device that comprises one or more power supplies. The programmable logic circuit receives information from the program. Subsequently, an illumination state of the LED is modified based on the information.

BACKGROUND

1. Field of the Invention

This disclosure relates generally to power distribution units, and more specifically to monitoring power source redundancy via a power distribution unit.

2. Description of the Related Art

Complex computer environments such as data centers contain multiple hardware devices, for example server computers, computer storage devices, and computer network equipment. The hardware devices have a variety of power needs and can be housed within a computer rack. To support the power needs of the hardware devices, power distribution units (PDUs) are utilized. The PDUs have multiple outlets (i.e., receptacles) that receive electrical power from a power source, and the outlets distribute the electrical power to the hardware devices via power cables that connect the outlets to power supplies of the hardware devices.

A service maintenance technician may experience difficulty in determining the location of a specific power cable that connects a power supply of a hardware device to an outlet of a PDU, because the power cable can be bundled together and covered by other power cables. For instance, often times within the complex computer environments, maintenance needs to be performed by a service maintenance technician on the hardware devices. To perform the maintenance, it may be necessary to disconnect one or more power cables of hardware devices, from outlets of PDUs in order to remove electrical power that is being supplied to the hardware devices. If the hardware devices are housed within a computer rack, for example a forty-two unit computer rack in which each unit has two power supplies, then there can be as many as eighty-four power cables running to multiple PDUs. Thus, if certain hardware devices have more than one power supply, then multiple power cables may have to be disconnected from the PDUs in order to ensure removal of electrical power to those hardware devices. Often the wrong power cables can be disconnected from the PDUs when trying to remove the electrical power to a hardware device, which can result in an unintentional shutdown of another hardware device that is operational and needs to remain on.

It is known for a person to physically trace the power cables that need to be disconnected, in order to locate the correct power cables and remove electrical power supplied to a specific hardware device. However, the power cables may be bundled together. As a result, a person may have to unbundle many power cables in order to physically trace certain power cables and remove the electrical power, which can be inefficient and increase the time to perform and complete maintenance tasks. Furthermore, it is also known to physically label each end of the power cables with handwritten or typewritten tags, which can assist with locating the correct power cables to disconnect from a PDU. However, trying to physically trace power cables and read tags on the power cables can be difficult because the power cables are often bundled together and housed within a tightly enclosed area that is not easily accessible to a person, such as a service maintenance technician.

SUMMARY

Aspects of an embodiment of the present invention disclose a method and program product for determining a power cable is suitable for disconnection from an outlet of a power distribution unit. A programmable logic circuit assigns a value to an outlet of a power distribution unit (PDU) that comprises a power source at an input of the PDU and at least one light-emitting diode (LED) associated with the outlet. The programmable logic circuit sends the value to a program on a hardware device that comprises one or more power supplies. The programmable logic circuit receives information from the program. Subsequently, an illumination state of the LED is modified based on the information.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The subject matter which is regarded as an embodiment of the present invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. One manner in which recited features of an embodiment of the present invention can be understood is by reference to the following detailed description of embodiments, taken in conjunction with the accompanying drawings in which:

FIG. 1A is a block diagram of a system having programmable logic circuit that modifies an illumination state of light-emitting diodes (LEDs) that are dedicated to specific outlets of a power distribution unit (PDU) in which each PDU has a single power source according to an embodiment of the present invention.

FIG. 1B is a block diagram of an alternative embodiment of the system, shown in FIG. 1A, having programmable logic circuit that modifies an illumination state of LEDs that are dedicated to specific outlets of a PDU in which each PDU has more than one power source according to an embodiment of the present invention.

FIG. 2A is an illustration of a PDU, shown in FIG. 1A, that receives electrical power from a single power source, and receives information on power supplies and power source conditions via a data communication port according to an embodiment of the present invention.

FIG. 2B is an illustration of a PDU, shown in FIG. 1B, that receives electrical power from more than one power source, and receives information on power supplies and power source conditions via a data communication port according to an embodiment of the present invention.

FIG. 3 is a flowchart illustrating operations of the programmable logic circuit within the PDU according to an embodiment of the present invention.

DETAILED DESCRIPTION

As will be appreciated by one skilled in the art, aspects of the present invention may be embodied as a system, method or computer program product. Accordingly, aspects of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit,” “module” or “system.” Furthermore, aspects of the present invention may take the form of a computer program product embodied in one or more computer readable medium(s) having computer readable program code embodied thereon.

Any combination of one or more computer readable medium(s) may be utilized. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.

A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.

Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

Computer program code for carrying out operations for aspects of the present invention may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C++ or the like, conventional procedural programming languages such as the “C” programming language, a hardware description language such as Verilog, or similar programming languages. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).

Aspects of the present invention are described below with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer readable medium that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the computer readable medium produce an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks.

The computer program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

Exemplary embodiments now will be described more fully herein with reference to the accompanying drawings. This disclosure may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art. In the description, details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the presented embodiments.

Embodiments of the present invention provide a technique for determining a power cable is suitable for disconnection from an outlet of a power distribution unit (PDU). The PDU includes a programmable logic circuit that modifies an illumination state of a light-emitting diode (LED) that is dedicated to a specific outlet of the PDU, based on information about power supplies and power source conditions. Particularly, the programmable logic circuit modifies the illumination state of the LED by activating, deactivating, or blinking the LED. The PDU having the programmable logic circuit and outlets with LEDs, can help a person determine power cables, of hardware devices, that are suitable for disconnection from outlets of the PDU.

If a hardware device is powered on, then the hardware device has one or more hardware power supplies that are functional. Power cables connected to the power supplies that are functional are not suitable for disconnection from an outlet of the PDU if the hardware device is powered on, because disconnecting the power cables may cause the hardware device to shutdown or lose power source redundancy. A hardware device has power source redundancy if the hardware device connects to at least two separate outlets that each distribute electrical power from a different power source.

Moreover, if the hardware device is powered on and has one or more non-functional power supplies, then power cables connected to the non-functional power supplies are suitable for disconnection from outlets of the PDU. Power cables are also suitable for disconnection from outlets of the PDU if the power cables are connected to power supplies of a hardware device that is powered off. Thus, power cables are suitable for disconnection if the hardware device is not utilizing the power cables as a transmission medium for receiving electrical power. Accordingly, if a hardware device is powered off, or the hardware device is powered on and has one or more power supplies that are non-functional, then LEDs corresponding to certain outlets connected to the hardware device will deactivate (i.e., certain LEDs will turn off). Particularly an LED corresponding to an outlet will deactivate if the outlet is connected, via a power cable, to a hardware device that is powered off. In addition, an LED corresponding to an outlet will deactivate if the outlet is connected via a power cable to a power supply, of a hardware device, that is non-functional. An LED that is deactivated indicates that it is safe to disconnect a power cable from an outlet corresponding to the LED.

Furthermore, certain power cables of hardware devices are not suitable for disconnection if the hardware devices are powered on, even if the hardware devices have power source redundancy. As described above, a hardware device has power source redundancy if the hardware device connects to at least two separate outlets that each distribute electrical power from a different power source. If the hardware device is powered on and has power source redundancy, then LEDs corresponding to outlets connected to functional power supplies of the hardware device will activate (i.e., LEDs will turn on). An LED that is activated indicates that it is unsafe to disconnect a power cable from an outlet corresponding to the LED, because disconnecting the power cable may lead to loss of power source redundancy for a hardware device.

In addition, if a hardware device is powered on and does not have power source redundancy, then LEDs corresponding to the outlets connected to functional power supplies of the hardware device will blink. A LED that blinks indicates that it is unsafe to disconnect a power cable from an outlet corresponding to the LED, because a hardware device connected to the outlet does not have power source redundancy and disconnecting the power cable may lead to total loss of electrical power to the hardware device.

FIG. 1A is a block diagram illustrating system 100 that includes PDU 105 a and 105 b having input 101 a and 101 b, power source 102 a and 102 b, network interface card 110 a and 110 b, power cables 115 a-118 a and 115 b-118 b, programmable logic circuit 120 a and 120 b, a group of outlets 125 a-128 a and 125 b-128 b, a group of LEDs 135 a-138 a and 135 b-138 b, and switch 140 a and 140 b, respectively. System 100 also includes one or more hardware devices 150 each having system management software 155 and one or more power supplies 160, wherein hardware devices 150 are connected to PDU 105 a and 105 b via network 108. Specifically, PDU 105 a and 105 b, utilizing network interface cards 110 a and 110 b, can be configured to communicate with system management software 155 via network 108. Network interface cards 110 a and 110 b include application firmware and hardware components that enable PDU 105 a and PDU 105 b respectively, to electronically communicate with hardware devices 150 (i.e., send and receive information). PDU 105 a and 105 b can be floor-mounted or housed within a computer rack. Moreover, outlets 125 a-128 a of PDU 105 a are connected to LEDs 135 a-138 a respectively, and outlets 125 b-128 b of PDU 105 b are connected to LEDs 135 b-138 b respectively. Power cables 115 a-118 a distribute electrical power from PDU 105 a to hardware devices 150, and power cables 115 b-118 b distribute electrical power from PDU 105 b to hardware devices 150. Particularly, power cables 115 a-118 a and 115 b-118 can connect outlets 125 a-128 a and 125 b-128 b to as many as eight separate power supplies 160.

In the disclosed embodiment, PDU 105 a and 105 b both distribute electrical power to hardware devices 150, but are connected to different power sources. PDU 105 a is connected to power source 102 a at input 101 a, whereas PDU 105 b is connected to power source 102 b at input 101 b. Thus, in the disclosed embodiment, each of hardware devices 150 can have power source redundancy if at least one of its power supplies 160 that is functional is connected to PDU 105 a, and if another one of its power supplies 160 that is functional is connected to PDU 105 b. Hardware devices 150 may be a computer with a workload (i.e., an application program executing in the computer and generally a number of end-users interacting with the computer's applications) deployed to accomplish a specific task within a virtualized infrastructure in which essential resources such as processing power, storage, and network bandwidth can be dynamically allocated as needed.

Furthermore, in regard to PDU 105 a, switch 140 a can communicate with programmable logic circuit 120 a to indicate which of outlets 125 a-128 a are connected to power source 102 a, by selecting a value that can be assigned by programmable logic circuit 120 a for each of outlets 125 a-128 a. Specifically, switch 140 a can be a dual-in-line package (DIP) switch having selectors that can be toggled to select a first value that can be assigned to each of outlets 125 a-128 a, wherein the first value represents power source 102 a. In the disclosed embodiment, power source 102 a distributes electrical power through input 101 a to all outlets 125 a-128 a. Thus, by utilizing switch 140 a and programmable logic circuit 120 a, each of outlets 125 a-128 a has the first value assigned to indicate that outlets 125 a-128 a are connected to power source 102 a. As described above, PDU 105 a is connected, via network 108, to hardware devices 150. Programmable logic circuit 120 a utilizes network 108 to transmit, for each of outlets 125 a-128 a, the first value and a PDU outlet identifier (PDU outlet ID) to system management software 155. Each of outlets 125 a-128 a has a unique PDU outlet ID, which allows each outlet 125 a-128 a to be individually identified. System management software 155 can utilize the first value received for each of outlets 125 a-128 a as part of determining whether hardware devices 150 have power source redundancy (i.e., whether hardware devices 150 are redundantly cabled to power sources 102 a and 102 b). For example, if power supplies 160 are functional and are all connected to a combination of outlets 125 a-128 a having the first value (i.e., having the same power source), then system management software 155 determines that the hardware devices 150 corresponding to the power supplies 160 do not have power source redundancy because the hardware devices 150 are connected to a combination of outlets 125 a-128 a that have the same power source.

Likewise, in regard to PDU 105 b, switch 140 b can communicate with programmable logic circuit 120 b to indicate which of outlets 125 b-128 b are connected to power source 102 b, by selecting a value that can be assigned by programmable logic circuit 120 b for each of outlets 125 b-128 b. In particular, switch 140 b can be a DIP switch having selectors that can be toggled to select a second value that can be assigned to each of outlets 125 b-128 b, wherein the second value represents power source 102 b. In the disclosed embodiment, power source 102 b distributes electrical power through input 101 b to all outlets 125 b-128 b. Thus, by utilizing switch 140 b and programmable logic circuit 120 b, each of outlets 125 b-128 b has the second value assigned to indicate that outlets 125 b-128 b are connected to power source 102 b. For each of outlets 125 b-128 b, programmable logic circuit 120 b transmits the second value and a PDU outlet ID, via network 108, to system management software 155. Each of outlets 125 b-128 b has a unique PDU outlet ID, which allows each outlet 125 b-128 b to be individually identified.

Subsequently, system management software 155 can process the first values, the second values, and PDU outlet IDs received and determine whether hardware devices 150 have power source redundancy. For example, if system management software 155 of a hardware device 150 receives a first value and a second value, then this indicates that the hardware device 150 is connected to a combination of outlets 125 a-128 a and 125 b-128 b having different power sources. Thus, if the hardware device 150 has power supplies 160 that are functional and connected to the combination of outlets 125 a-128 a and 125 b-128 b having different power sources, then system management software 155 processes the first value and second value and determines that the hardware device 150 has power source redundancy. However, if the system management software 155 of a hardware device 150 receives only one or more first values or only one or more second values, then this indicates that the hardware device 150 is connected to a combination of outlets 125 a-128 a or 125 b-128 b not having different power sources. Consequently, system management software 155 processes the one or more first values or second values and determines that the hardware device 150 does not have power source redundancy.

After making a determination on power source redundancy, of hardware devices 150, system management software 155 can send information about power supplies 160 and power source conditions to programmable logic circuit 120 a and 120 b. Specifically, the information that system management software 155 can send to programmable logic circuit 120 a and 120 b includes the following: outlets 125 a-128 a and 125 b-128 b that are connected to hardware devices 150 via power supplies 160, whether hardware devices 150 are powered on, whether hardware devices 150 are powered off, whether hardware devices 150 are receiving electrical power via power supplies 160 from at least two different power sources, outlets 125 a-128 a and 125 b-128 b that are connected to power supplies 160 that are non-functional, and outlets 125 a-128 a and 125 b-128 b that are connected to power supplies 160 that are functional.

As mentioned above, programmable logic circuit 120 a and 120 b receive the information from system management software 155. Programmable logic circuit 120 a and 120 b can utilize the information to activate, deactivate, or blink one or more LEDs 135 a-138 a and 135 b-138 b, respectively. Programmable logic circuit 120 a and 120 b may be implemented utilizing a microprocessor or an integrated circuit such as a field-programmable gate array (FPGA), which can be programmed by an end-user. In addition, in the disclosed embodiment, PDU 105 a and 105 b each have four outlets 125 a-128 a and 125 b-128 b, respectively. In other embodiments (not shown) PDU 105 a and 105 b may each have only one outlet or as many as forty outlets, wherein each outlet can have its own corresponding LED.

FIG. 1B is a block diagram illustrating an alternative embodiment of system 100 that includes PDU 105 a and 105 b having power source 102 a and 102 b at each input 101 a and 101 b. In the alternative embodiment, each of hardware devices 150 can have power source redundancy by utilizing either PDU 105 a alone or PDU 105 b alone, because input 101 a and 101 b are each connected to power source 102 a and 102 b such that PDU 105 a and 105 b can each distribute electrical power from power source 102 a and 102 b. Thus, in the alternative embodiment, PDU 105 a can provide power source redundancy for hardware devices 150 by utilizing switch 140 a to select the first value that can be assigned to a portion of outlets 125 a-128 a connected to power source 102 a, and select the second value that can be assigned to a portion of outlets 125 a-128 a connected to power source 102 b. Similarly, PDU 105 b can provide power source redundancy by utilizing switch 140 b to select the first value that can be assigned to a portion of outlets 125 b-128 b connected to power source 102 a, and select the second value that can be assigned to a portion of outlets 125 b-128 b connected to power source 102 b. As described above the first value represents power source 102 a, and the second value represents power source 102 b. Moreover, in the alternative embodiment, PDU 105 a and 105 b each have four outlets 125 a-128 a and 125 b-128 b, respectively. In other embodiments (not shown) PDU 105 a and 105 b may each have only two outlets or as many as forty outlets, wherein each outlet can have its own corresponding LED.

FIG. 2A illustrates PDU 105 a, shown in FIG. 1A, having outlets 125 a-128 a, LEDs 135 a-138 a, switch 140 a, data communication port 142, and power cord 144 with plug 145. PDU 105 a can receive electrical power from a single power source (e.g., power source 102 a) via power cord 144 and can distribute the electrical power through outlets 125 a-128 a to hardware devices 150. In addition, PDU 105 a can receive information about power supplies 160 and power source conditions through data communication port 142, wherein programmable logic circuit 120 a can process the information and activate, deactivate, or blink one or more LEDs 135 a-138 a based on the information.

FIG. 2B illustrates PDU 105 a, shown in FIG. 1B, having outlets 125 a-128 a, LEDs 135 a-138 a, switch 140 a, data communication port 142, power cord 144 with plug 145, and power cord 146 with plug 147. PDU 105 a can receive electrical power from two power sources (e.g., power source 102 a and 102 b) via power cord 144 and 146 and can distribute the electrical power through outlets 125 a-128 a to hardware devices 150. In addition, PDU 105 a can receive information about power supplies 160 and power source conditions through data communication port 142, wherein programmable logic circuit 120 a can process the information and activate, deactivate, or blink one or more LEDs 135 a-138 a based on the information.

FIG. 3 is a flowchart 300 illustrating operations of programmable logic circuit 120 a and 120 b within PDU 105 a and 105 b, respectively. However, for simplicity the flowchart is explained in terms of programmable logic circuit 120 a. To begin the operations, values are selected for outlets 125 a-128 a by utilizing switch 140 a, wherein the values represent power sources at input 101 a of PDU 105 a. Programmable logic circuit 120 a assigns a value to each outlet 125 a-128 a of PDU 105 a (block 300). Next, programmable logic circuit 120 a sends the value and a PDU outlet ID to system management software 155 on hardware devices 150, for each outlet 125 a-128 a having an LED (block 305). System management software 155 processes the value to determine whether the hardware device 150 has power source redundancy. Specifically, system management software 155 on a hardware device 150 can determine that hardware device 150 has power source redundancy if system management software receives at least two different values (i.e., a first value and a second value) that each have different PDU outlet IDs. Next system management software 155 sends information to programmable logic circuit 120 a. The information includes the following: outlets 125 a-128 a and 125 b-128 b that are connected to hardware devices 150 via power supplies 160, whether hardware devices 150 are powered on, whether hardware devices 150 are powered off, whether hardware devices 150 are receiving electrical power via power supplies 160 from at least two different power sources, outlets 125 a-128 a and 125 b-128 b that are connected to power supplies 160 that are non-functional, and outlets 125 a-128 a and 125 b-128 b that are connected to power supplies 160 that are functional.

Programmable logic circuit 120 a receives the information from system management software 155 (block 310). Next, if programmable logic circuit 120 a determines that the information indicates hardware device 150 is powered off (“NO” branch of decision block 315), then programmable logic circuit 120 a deactivates the LED (e.g., LED 135 a-138 a) of each outlet 125 a-128 a that is connected, via a power cable, to hardware device 150 (block 320). Subsequently, further processing by programmable logic circuit 120 a ends. However, if programmable logic circuit 120 a determines that the information indicates hardware device 150 is powered on (“YES” branch of decision block 315), then programmable logic circuit 120 a determines if the information indicates hardware device 150 has non-functional power supplies 160.

If programmable logic circuit 120 a determines that the information indicates hardware device 150 does not have non-functional power supplies 160 (“NO” branch of decision block 325), then programmable logic circuit 120 a determines if the information further indicates hardware device 150 has power source redundancy. If programmable logic circuit 120 a determines that the information further indicates hardware device 150 has power source redundancy (“YES” branch of decision block 335), then programmable logic circuit 120 a activates the LED (e.g., LED 135 a-138 a) of each outlet 125 a-128 a connected, via a power cable, to functional power supplies 160 of hardware device 150 (block 340). Subsequently, further processing by programmable logic circuit 120 a ends.

However, if programmable logic circuit 120 a determines that the information indicates hardware device 150 has non-functional power supplies 160 (“YES” branch of decision block 325), then programmable logic circuit 120 a deactivates the LED (e.g., LED 135 a-138 a) of each outlet 125 a-128 a connected, via a power cable, to non-functional power supplies 160 of hardware device 150 (block 330). Subsequently, if programmable logic circuit 120 a determines that the information indicates hardware device 150 has power source redundancy (“YES” branch of decision block 335), then programmable logic circuit 120 a activates the LED (e.g., LED 135 a-138 a) of each outlet 125 a-128 a connected, via a power cable, to functional power supplies 160 of hardware device 150 (block 340). However, if programmable logic circuit 120 a determines that the information indicates hardware device 150 does not have power source redundancy (“NO” branch of decision block 335), then programmable logic circuit 120 a blinks the LED (e.g., LED 135 a-138 a) of each outlet connected via a power cable to functional power supplies 160 of hardware device 150 (block 345). Next, further processing by programmable logic circuit 120 a ends.

Flowchart 300 depicted in FIG. 3 illustrates the functionality and operation of possible implementations of a programmable logic circuit within a PDU having outlets in which each outlet has an LED, according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

Lastly, the foregoing description of various aspects of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed and, obviously, many modifications and variations are possible. Such modifications and variations that may be apparent to a person skilled in the art are intended to be included within the scope of the invention as defined by the accompanying claims. 

What is claimed is:
 1. A method for determining a power cable is suitable for disconnection from an outlet of a power distribution unit, the method comprising: assigning, by a programmable logic circuit, a first value to an outlet of a power distribution unit (PDU), the outlet located in close proximity to an indicator, the first value including a first identifier identifying a first PDU and a first name representing a first power source; sending, by the programmable logic circuit and through a communication network, the first value to a program on a hardware device that comprises one or more power supplies and is powered by the outlet; receiving, by the programmable logic circuit and through the communication network, information from the hardware device related to the status of the one, or more, power supplies coupled to the outlet; and modifying an indication state of the indicator based, at least in part, on the information.
 2. The method of claim 1, wherein assigning the first value comprises utilizing a switch to select the first value.
 3. The method of claim 2, wherein the switch is a dual-in-line package (DIP) switch having selectors that toggle to select the first value.
 4. The method of claim 1, wherein the hardware device is deployed to accomplish a specific task within an infrastructure in which essential resources such as processing power, storage, and network bandwidth can be allocated as needed.
 5. The method of claim 1, wherein the information includes the following: any outlets connected to the hardware device via the one or more power supplies, whether the hardware device is powered on, whether the hardware device is powered off, whether the hardware device is receiving electrical power via the one or more power supplies from at least two different power sources, each power source associated with a corresponding name, any outlets that are connected to the one or more power supplies that are non-functional, and any outlets that are connected to the one or more power supplies that are functional.
 6. The method of claim 1, wherein modifying the indication state of the indicator based, at least in part, on the information comprises: determining the hardware device is powered on and is receiving electrical power, via the one or more power supplies, from at least two different power sources, including the first power source represented by the first name and a second power source represented by a second name, and activating the indicator.
 7. The method of claim 1, wherein modifying the indication state of the indicator based, at least in part, on the information comprises: determining the hardware device is powered off, and deactivating the indicator.
 8. The method of claim 1, wherein modifying the indication state of the indicator based, at least in part, on the information comprises: determining the hardware device is powered on and the outlet is connected to one of the one or more power supplies that are non-functional, and deactivating the indicator.
 9. The method of claim 1, wherein modifying the indication state of the indicator based, at least in part, on the information comprises: determining the hardware device is powered on and is not receiving electrical power, via the one or more power supplies, from at least two different power sources, including the first power source represented by the first name and a second power source represented by a second name, and blinking the indicator.
 10. The method of claim 1, wherein sending, by the programmable logic circuit and through the communication network, the first value to the program on the hardware device comprises: sending a unique ID associated with the outlet in which the unique ID allows the outlet to be individually identified by the program on the hardware device.
 11. A computer program product for determining a power cable is suitable for disconnection from an outlet of a power distribution unit comprising: a non-transitory computer readable storage device and program instructions stored on the non-transitory computer readable storage device, the program instructions comprising: program instructions to assign, by a programmable logic circuit, a first value to an outlet of a power distribution unit (PDU), the outlet located in close proximity to an indicator, the first value including a first identifier identifying a first PDU and a first name representing a first power source; program instructions to send, by the programmable logic circuit and through a communication network, the first value to a program on a hardware device that comprises one or more power supplies and is powered by the outlet; program instructions to receive, by the programmable logic circuit and through the communication network, information from the hardware device related to the status of the one, or more, power supplies coupled to the outlet; and program instructions to modify an indication state of the indicator based, at least in part, on the information.
 12. The computer program product of claim 11, wherein the program instructions to assign the first value comprises utilizing a switch to select the first value.
 13. The computer program product of claim 12, wherein the switch is a dual-in-line package (DIP) switch having selectors that toggle to select the first value.
 14. The computer program product of claim 11, wherein the hardware device is deployed to accomplish a specific task within an infrastructure in which essential resources such as processing power, storage, and network bandwidth can be allocated as needed.
 15. The computer program product of claim 11, wherein the information includes the following: any outlets connected to the hardware device via the one or more power supplies, whether the hardware device is powered on, whether the hardware device is powered off, whether the hardware device is receiving electrical power via the one or more power supplies from at least two different power sources, each power source associated with a corresponding name, any outlets that are connected to the one or more power supplies that are non-functional, and any outlets that are connected to the one or more power supplies that are functional.
 16. The computer program product of claim 11, wherein the program instructions to modify the indication state of the indicator based, at least in part, on the information comprises determining the hardware device is powered on and is receiving electrical power, via the one or more power supplies, from at least two different power sources, including the first power source represented by the first name and a second power source represented by a second name, and activating the indicator.
 17. The computer program product of claim 11, wherein the program instructions to modify the indication state of the indicator based, at least in part, on the information comprises determining the hardware device is powered off, and deactivating the indicator.
 18. The computer program product of claim 11, wherein the program instructions to modify the indication state of the indicator based, at least in part, on the information includes: program instructions to determine the hardware device is powered on and the outlet is connected to one of the one or more power supplies that are non-functional, and deactivating the indicator.
 19. The computer program product of claim 11, wherein the program instructions to modify the indication state of the indicator based, at least in part, on the information includes: program instructions to determine the hardware device is powered on and is not receiving electrical power, via the one or more power supplies, from at least two different power sources, including the first power source represented by the first name and a second power source represented by a second name, and blinking the indicator.
 20. The computer program product of claim 11, wherein the program instructions to send, by the programmable logic circuit and through the communication network, the first value to the program on the hardware device includes: program instructions to send a unique ID associated with the outlet in which the unique ID allows the outlet to be individually identified by the program on the hardware device. 